CAJ | 학술논문

电火花线切割加工变厚度工件时的断丝和效率低下现象是线切割加工需解决的主要问题。根据工件厚度选择加工参数可避免加工过程中的断丝现象，并提高加工效率。基于工件三维模型提取的工件厚度不但能直接用于指导加工过程中的参数选取，还能用于在线修正工件厚度辨识模型。基于最小二乘支持向量机的在线算法动态更新工件厚度辨识模型，可使模型包含的信息更丰富，辨识精度更高。在加工没有三维模型的工件时，利用不断修正的辨识模型也可估计出准确的工件厚度用于指导加工过程。实验数据验证了该在线算法的有效性，辨识精度小于2 mm。
전화화선절할가공변후도공건시적단사화효솔저하현상시선절할가공수해결적주요문제。근거공건후도선택가공삼수가피면가공과정중적단사현상，병제고가공효솔。기우공건삼유모형제취적공건후도불단능직접용우지도가공과정중적삼수선취，환능용우재선수정공건후도변식모형。기우최소이승지지향량궤적재선산법동태경신공건후도변식모형，가사모형포함적신식경봉부，변식정도경고。재가공몰유삼유모형적공건시，이용불단수정적변식모형야가고계출준학적공건후도용우지도가공과정。실험수거험증료해재선산법적유효성，변식정도소우2 mm。
When machining workpieces with a variable height, wire breakage and low machining efficiency are the two major issues. For variable height WEDM, the workpiece height must be provided so that appropriate machining parameters can then be determined according to it. The workpiece height extracted from the 3D model can be directly applied to the CNC system. Not only can this data be used to control the machining process in progress, but also can be used to update the workpiece height estimation model online. The update of the workpiece height estimation model was achieved by using the online least square support vector machine. By learning the new dynamics which have not been excited before, the height estimation model can be refined, thus improving its prediction accuracy. Experimental results show that, by online learning, the estimation model becomes more accurate and a much higher estimation precision is thus obtained. The value of estimation errors at most parts of the workpiece is less than 2 mm.